1. The problem statement, all variables and given/known data For an upcoming test on 2D Motion, my Physics Teacher recommended that, instead of memorizing close to a dozen equations, he suggested we derive what we can from the main equations he showed us. So people in my class decided to split up deriving equations to bring them together later for everyone to use. I was told to use these two: y = (Vosin(theta))t - 1/2gt^2 Vy = Vosin(theta) - gt So I was attempting to derive Vy from y, but found an issue. 2. Relevant equations y = (Vosin(theta))t - 1/2gt^2 Vy = (Vosin(theta)) - gt V = d/t 3. The attempt at a solution To derive Vy, I simply did ((Vosin(theta))t - 1/2gt^2)) / t. This gave me (Vosin(theta)) - 1/2gt. This differs from the given equation for Vy, so I'm curious what I have to do to cancel out the 1/2.